As animal litter for use in animal toilets for cats and the like that are raised indoors, there are widely known types that employ as the major starting material, for example, bentonite that swells and exhibits cohesive force upon absorption of urine and fluids in excreta, or that comprise various kinds of materials, such as paper molded into pellets (pellet types).
Such animal litter is subjected to treatment, such as heating after being molded into pellets, and then filled and wrapped in prescribed amounts in containers, such as bags for shipment as a product, and shipped. When such animal litter is filled into a container, the animal litter is first stored in a storage hopper and then passed through multiple delivery holes provided in the hopper, whereby the animal litter in the hopper is filled in prescribed amounts into multiple containers.
The animal litter is sometimes formed with different particle diameters during molding, or commonly portions may be removed and broken up during transport after molding, creating animal litter with smaller particle diameters than the designed particle diameters. Consequently, the animal litter includes large-sized granules having the pre-designed particle diameters, and small-sized granules having particle diameters that are smaller than the large-sized granules.
On the other hand, when only large-sized granules are filled into a container during filling of the animal litter into a container, relatively large spaces form between the adjacent large-sized granules. When this occurs, the amount that can be filled into the container is reduced and it may not be possible to ensure the prescribed absorbing power for animal excreta to be exhibited by the full amount of animal litter filled into a single container.
In recent years, therefore, filling has been carried out while combining the large-sized granules and small-sized granules in a single container, so that the small-sized granules become disposed in the spaces formed by the multiple large-sized granules, thereby increasing the overall surface area of the animal litter filled in the single container and ensuring the prescribed absorbing power for animal excreta.
As mentioned above, when the large-sized granules and small-sized granules are combined and filled into a single container, it is necessary to fill the large-sized granules and small-sized granules into the container in the prescribed blending ratio. Also, when animal litter is filled into a container, and the blending ratio of the large-sized granules and small-sized granules is significantly different from that in other containers, this may result in differences in absorbing power of the entire animal litter filled into each of the containers, and for this reason it is necessary to consistently combine the animal litter in a fixed blending ratio.
Consequently, as described in PTL 1 for example, the large-sized granules and small-sized granules are stored in separate hoppers while a prescribed amount of the small-sized granules delivered from the small-sized granule hopper are combined with the large-sized granules delivered from the large-sized granule hopper, and they are then filled into the containers.
With the type described in PTL 1 it is necessary to store the large-sized granules and small-sized granules in separate hoppers, and therefore a large space is required. Also, since it is necessary to provide separate apparatuses for combination of the small prescribed amounts of small-sized granules with the large-sized granules, this has led to the problem of increased size and complexity of the equipment used to fill the animal litter into containers.